The invention relates to an integrated monolithic circuit having a predetermined internal structure and comprising a functional circuit which is partitioned into at least two macro circuits and test interface circuits which are coupled to the macro circuits, the functional circuit being coupled to external connections and the test interface circuits being coupled to one another.
An integrated monolithic circuit of this kind is described in an article by Beenker et al. "Macro Testing" in IEEE DESIGN & TEST, Dec. 1986, pp. 26-32. The article by Beenkez et al proposes the partitioning into macro circuits for the testing of a digital circuit, being either an integrated monolithic circuit or a circuit consisting of a number of integrated monolithic circuits which are grouped on a board so as to form a digital circuit, a macro circuit being related to a partitioning into building blocks (such as RAM (random access memory), ROM (read-only memory), multipliers and ALU (arithmetic and logic unit)) which is customarily used for VLSI (very large scale integration) design methods. The digital circuit as a whole forms a functional circuit. When the digital circuit is accommodated in one integrated monolithic circuit, it is coupled to external connections of the integrated monolithic circuit. Via test interface circuits (see inter alia FIG. 3 of the cited article), inputs and/or outputs of the macro circuits are accessible for test purposes. A method of coupling as described in said article on page 30 is the coupling of the test interface circuits so as to form a shift register. Under the control of a clock signal, predetermined data is shifted into the shift register. Correct operation of the functional circuit can be verified by analysis of the data shifted out of the shift register. The nature of digital circuits is suited to such a method of testing. The correct operation of a digital circuit can be verified on the basis of the analyzed data which thus may become available (many) clock periods later than the applied data. Such a method of testing, however, is not suited to the testing of a (mainly) analog functional circuit. In the case of an analog circuit the response to an input signal is virtually immediately (real time) available as the output signal which cannot be stored in, for example a flip flop such as in the case of digital macro circuits (combinatory, sequential or a combination thereof). The macro circuits of an analog functional circuit will usually be highly interrelated (real time). Furthermore, for each new design the proposed method of testing, using additional hardware added to the integrated monolithic circuit for test purposes, makes it necessary to determine the method of coupling the macro circuits to the test interface circuits completely a new, together with the associated test software, during the design phase of the integrated monolithic circuit. A strong relationship exists between the design of the functional and the additional hardware and the test software to be generated.